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Diffstat (limited to 'src/math/atan2l.c')
-rw-r--r--src/math/atan2l.c50
1 files changed, 22 insertions, 28 deletions
diff --git a/src/math/atan2l.c b/src/math/atan2l.c
index e0167d09..f0937a97 100644
--- a/src/math/atan2l.c
+++ b/src/math/atan2l.c
@@ -27,56 +27,50 @@ long double atan2l(long double y, long double x)
long double atan2l(long double y, long double x)
{
- union IEEEl2bits ux, uy;
+ union ldshape ux, uy;
long double z;
- int m;
- uint16_t exptx, expsignx, expty, expsigny;
+ int m, ex, ey;
if (isnan(x) || isnan(y))
return x+y;
if (x == 1)
return atanl(y);
- uy.e = y;
- expsigny = uy.xbits.expsign;
- expty = expsigny & 0x7fff;
- ux.e = x;
- expsignx = ux.xbits.expsign;
- exptx = expsignx & 0x7fff;
- m = ((expsigny>>15)&1) | ((expsignx>>14)&2); /* 2*sign(x)+sign(y) */
-
+ ux.f = x;
+ uy.f = y;
+ ex = ux.i.se & 0x7fff;
+ ey = uy.i.se & 0x7fff;
+ m = 2*(ux.i.se>>15) | uy.i.se>>15;
if (y == 0) {
switch(m) {
case 0:
case 1: return y; /* atan(+-0,+anything)=+-0 */
- case 2: return 2*pio2_hi+0x1p-120f; /* atan(+0,-anything) = pi */
- case 3: return -2*pio2_hi-0x1p-120f; /* atan(-0,-anything) =-pi */
+ case 2: return 2*pio2_hi; /* atan(+0,-anything) = pi */
+ case 3: return -2*pio2_hi; /* atan(-0,-anything) =-pi */
}
}
if (x == 0)
- return m&1 ? -pio2_hi-0x1p-120f : pio2_hi+0x1p-120f;
- /* when x is INF */
- if (exptx == 0x7fff) {
- if (expty == 0x7fff) {
+ return m&1 ? -pio2_hi : pio2_hi;
+ if (ex == 0x7fff) {
+ if (ey == 0x7fff) {
switch(m) {
- case 0: return pio2_hi*0.5+0x1p-120f; /* atan(+INF,+INF) */
- case 1: return -pio2_hi*0.5-0x1p-120f; /* atan(-INF,+INF) */
- case 2: return 1.5*pio2_hi+0x1p-120f; /* atan(+INF,-INF) */
- case 3: return -1.5*pio2_hi-0x1p-120f; /* atan(-INF,-INF) */
+ case 0: return pio2_hi/2; /* atan(+INF,+INF) */
+ case 1: return -pio2_hi/2; /* atan(-INF,+INF) */
+ case 2: return 1.5*pio2_hi; /* atan(+INF,-INF) */
+ case 3: return -1.5*pio2_hi; /* atan(-INF,-INF) */
}
} else {
switch(m) {
case 0: return 0.0; /* atan(+...,+INF) */
case 1: return -0.0; /* atan(-...,+INF) */
- case 2: return 2*pio2_hi+0x1p-120f; /* atan(+...,-INF) */
- case 3: return -2*pio2_hi-0x1p-120f; /* atan(-...,-INF) */
+ case 2: return 2*pio2_hi; /* atan(+...,-INF) */
+ case 3: return -2*pio2_hi; /* atan(-...,-INF) */
}
}
}
- /* when y is INF */
- if (exptx+120 < expty || expty == 0x7fff)
- return m&1 ? -pio2_hi-0x1p-120f : pio2_hi+0x1p-120f;
-
- if ((m&2) && expty+120 < exptx) /* |y/x| tiny, x<0 */
+ if (ex+120 < ey || ey == 0x7fff)
+ return m&1 ? -pio2_hi : pio2_hi;
+ /* z = atan(|y/x|) without spurious underflow */
+ if ((m&2) && ey+120 < ex) /* |y/x| < 0x1p-120, x<0 */
z = 0.0;
else
z = atanl(fabsl(y/x));